Just the Biased Facts

We like to think of ourselves as rational actors when it comes to making decisions, we take in information, process it and choose the path that we think will lead to a desirable outcome (if we aren’t deep-seated masochists I suppose). Regular readers of this blog and others that espouse a sceptical viewpoint will know that this isn’t really the case. We are influenced by a large number of factors from implicit biases, to environmental factors, and errors of thinking. The hope is that if we are aware of these factors we can go some way toward mitigating their effects and making choices that are both rational and lead to improving our lives.

Well, here’s another one for you. You may have guessed by the title of this post that it involves food and risk taking behaviour. A paper published last month in PLoS ONE out of the University College London looked at how hunger and food intake affected choices that had a monetary reward. The actual experimental design ran something like this, subjects fasted for 14 hours they then performed tasks that in effect were an idealised lottery, the tasks were performed before, directly after and an hour after a standardised meal. Over this time the subjects also had blood samples taken to measure hormones that correlate with hunger and energy reserves.

The task subjects had to perform consisted of choosing one of a pair of “lotteries” where there was a 25% chance of receiving one of four monetary amounts. Each pairing was designed so that there was always a difference in risk between the two (see the picture it’s hard to explain).

Paired Lottery doi:10.1371/journal.pone.0011090.g002

How the subjects performed on the tasks was measured to determine the amount of risk aversion. In other words, humans have a tendency to normally prefer less risky choices. The effect of of hunger and especially immediate satiation (right after eating the meal) is to decrease this risk aversion and to make the subjects more risk neutral.

This way of referring to the subject matter is a little counter intuitive and can take a bit of getting used to, the bottom line is that the researchers looked for the point at which the subjects were equally likely to choose the “safe” bet which promised an certain average reward, and a “risky” bet that may lead to a higher average pay off but a lower chance of receiving it. Thus risk aversion has been reduced. By varying the reward amounts the researchers can measure the degree of risk aversion in each subject as the trial proceeds.

Actually the correlation is more complex than I would have thought, not only is the fact that calories are received taken into account but also the amount of calories. It seems that the size of the meal (in terms of calorific intake) is assessed to determine if it meets the rate of food intake required to meet baseline energy requirements. If it does risk aversion is increased (less risky behaviour) if not the risk aversion is decreased.

In hormonal terms this meant that a greater drop in the hormone associated with hunger was correlated with greater risk aversion but a smaller drop meant an increase in risk taking behaviour. The study authors also note that the adiposity of an individual (eg higher BMI) correlated with the size of the hormonal decrease after eating with higher BMI subjects experiencing a smaller drop and a corresponding greater increase in risk taking behaviour.

In effect we not only look at the reward in terms of the gain we will receive compared to our external resources (cash in the bank, say) but also in relation to our internal resources (metabolic requirements for example). This makes sense if we consider that for most of our history true advantage was not measured in abstract accumulation of “wealth” which we would recognise today but in available energy, including that within our bodies. That’s just a speculation of course, I’m no expert in this area.

What is the take home message of this research then? Well first off we should be careful to realise that risk taking behaviour is not limited to single domains in our lives. If you take away from this that only financial decisions are affected then that is too narrow an interpretation. In the final analysis though, no matter our eating habits or body size, we should endeavour to think over important decisions carefully and be aware of the changeable nature of our biology and it’s effects on our thinking.

Last week I posted about the effects of alcohol availability on the amount of violence in an area and mentioned that disorder in the area might also contribute to this. I thought this needed expanding upon, are we really so shallow as a species that we allow the environment that we may be in only briefly to dictate how we behave?

This approach to behaviour is referred to as the Broken Windows Theory and states that signs of disorderly behaviour will beget more disorderly behaviour. These signs might be graffiti, littering or the observation that legitimate signage requesting a particular behaviour is being ignored. We are a species that learns by watching others, it is reasonable to conclude that we don’t only pick up good and productive behaviours in this way but potentially antisocial or destructive behaviours as well.

Acting on this theory cities around the world have embarked on projects to clean up urban areas in order to reduce the instance of petty crime. Trouble was that there was no conclusive evidence to back this theory up. A paper that goes some way towards rectifying this was published in late 2008. It looked at the effects of manipulating the environment on the propensity for people to break either social norms, police enforced ordinances or requests by companies.

The paper hypothesised that people were not merely copying behaviours but that indications of social or legal norms not being followed in an area allowed other personal goals to override our normal instincts to act in socially acceptable ways. To investigate this the researchers set up conditions to see if the breaking of one rule lead to the breaking of a different rule e.g. graffiti leading to littering or litter leading to stealing.

In all 6 studies were performed, in the first an ally where bicycles were commonly parked was set up to have either clean or graffiti covered walls. The effect of this environment on littering was then observed by attaching a useless flyer onto the bicycle handlebars and counting instances of littering compared to those that took the flyer with them (there were no bins in the ally). In the clean wall condition 33% of those collecting bikes littered, compared with 69% in the graffiti condition.

In the second study the conditions were whether an injunction to not lock bicycles to a fence would affect whether or not people would take a police sanctioned detour. Two signs were placed along the fence of a car-park, the first prohibited locking bicycles to the fence while the second advised that the closest entrance to the car-park was closed and that a second entrance 200 metres further along had to be used. The entrance was closed with a temporary fence but a gap left that could be used. Bicycles were then conspicuously left either locked or not locked to the fence. When the bicycles were not locked to the fence 73% of people entering the car-park took the detour compared with only 18% when the bikes were seen violating the sign.

I think we can see a pattern emerging. I’m going to skip the third and forth studies that are variations on the littering theme and to go straight for the fifth and sixth. These two studies concerned stealing and had very similar set-ups, an envelope visibly containing a €5 note was set-up hanging out of a mail collection box. The box was then either clean and the area around it tidy or the box was graffitied or there was litter around the box. Taking or opening the envelope were both counted as stealing. The clean and tidy condition resulted in 13% of passers-by stealing the envelope, whereas the graffiti and litter conditions resulted in 27% and 25% of people stealing respectively.

What does this tell us about human behaviour? First off I see it as very positive, social conventions are a powerful factor for encouraging acceptable behaviour, on balance people prefer to act responsibly in the absence of cues that suggest irresponsible behaviour is tolerated. This suggests that policing general behaviour may be achieved in a subtle fashion by re-enforcing social conventions rather than with actual shows of force and punishment. That said the authors of the paper take a slightly more pessimistic view of areas that have already succumbed to spreading disorder, concluding with this thought:

“.. once disorder has spread, merely fixing the broken windows or removing the graffiti may not be sufficient anymore. An effective intervention should now address the goal to act appropriately on all fronts.”

The trick then is prevention rather than clean-up, at least in areas where behaviours have become entrenched. I think this is good news over all.

Check out these completely entrancing records of science. Unfortunately I couldn’t embed them in this post. Wrong format, wrong presentation style. So use this link to go directly to the part of the paper that links to the videos.

Rhyming Prose

Vital impulse synaptically flow
through neurons, til they go.
Lost without a trace
not to some other place.
The end may be final
but our legacy is ample
to ensure our continued existence
though our life's a single instance.